Intraocular lens and method for making same

ABSTRACT

A colored ringed or rimmed edge intraocular lens for implant in either the anterior chamber, the posterior chamber or the cornea of the eye. The lens has a colorless or clear central region of a material such as polymethylmethacrylate (PMMA) and a peripheral surrounding portion of a dark material such as blue PMMA. Polysulfone can also be utilized. The lens can be fabricated by passing a clear rod of optical quality PMMA through an extrusion orifice and coating the circumference of the rod with a layer of predetermined thickness of colored, preferably blue PMMA or other compatible material. Other methods of fabrication can include the introduction of a suitable dye into the outer regions of the rod, or joining the clear central region to a ring of colored material by thermal or adhesive bonding or other known processes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to intraocular lenses including a ring orrim of colored material, and more particularly, pertains to thereduction of glare resulting from the edge effect and from the lighttransmitted from the positioning loops to the lens itself.

2. Description of the Prior Art

None of the prior art lenses known to applicant have utilized structurefor reduction of glare resulting from the edge effect and from the lighttransmitted through the positioning loops to the lens itself.

The edges of a lens are known to cause glare as a result of the lightwhich is incident on the lens but which is not brought to a focus on theretina. Because the loops are generally made from the same material asthe central portion, the light falling on the loops is transmitted tothe lens itself, causing glare and reflections which are distracting anduncomfortable.

The present invention overcomes the disadvantages by providing a darkerregion which reduces the intensity of the light transmitted from theedge of the lens and from positioning loops to the central region.

SUMMARY OF THE INVENTION

The general purpose of the present invention is to provide anintraocular lens or intracorneal lens with a ring or rim of coloredmaterial which minimizes glare, and distracting reflections caused bythe edge effect and from the light transmitted from the positioningloops to the lens itself.

One preferred embodiment of the present invention is a lens which has aring or rim peripheral portion which is a darker color, serving toreduce the intensity of the light transmitted through the loops to thecentral portion of the lens. The lens can be an anterior chamber lens orposterior chamber lens with loop or an intracorneal lens.

One preferred method of fabrication is to coat a clear rod of PMMA witha darker outer layer through an extrusion process. Alternative methodsof manufacture include the introduction of a dye into the outer layersof the clear PMMA rod.

Having thus described several embodiments of the present invention, itis the principal object hereof to provide an intraocular or intracorneallens which is substantially devoid of glare and reflections caused bylight transmitted to the lens through the positioning loops, holes, oredges of the lens.

One object of the present invention is to provide a method forfabrication of an intraocular lens which possesses improved quality ofvision because of the reduced glare and reflections normally introducedby the positioning loops or edges of the lens.

Another object of the present invention is to provide cylindrical boulemember with a colored ring or rim, which lens can be lathe cut.

A further object of the present invention are positioning holes andradial loop holes in the colored ring minimizing glare from the holes.

An additional object of the present invention is a single-piece positivelens with colored haptics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top view of an intraocular lens showing the darkperipheral portion according to the present invention;

FIG. 2 illustrates a sectional view along the line 2--2 of the lensshown in FIG. 1;

FIG. 3 is a cross sectional view of a rod of transparent material ringeddark material;

FIGS. 4a, 4b, and 4c show the material used to fabricate the lens invarious stages of manufacture;

FIGS. 5a, 5b, and 5c show the material used to fabricate the lens atvarious stages of an alternate method of manufacture; and,

FIG. 6 illustrates an enlarged view of the portion of FIG. 5b enclosedin dotted line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates an intraocular lens 10 including a lens optic 12 andtwo positioning loops 14 and 16. The lens optic 12 includes a clearcentral portion 20 and a colored peripheral portion 12. The entireassembly is made of any suitable material, preferably PMMA oralternative materials such as polysulfone.

The colored ring or rim portion 22 is sufficiently darker in color tosubstantially reduce the intensity of light transmitted from the outeredge to the clear central portion 20. While the transmissivity of theportion 22 is preferably reduced by coloring with a darker color thanthe transparent section, such as blue, the transmissivity can be reducedby other processes as well. The width of the colored portion 22 isselected to provide adequate space for the attachment of the loops 14and 16 by processes such as staking, adhesive bonding, or ultrasonicbonding. The width of the colored portion 22 is also sufficient toprovide adequate reduction in the intensity of the light transmittedfrom the periphery 12 to the central portion 20 of the lens 10. Theloops 14 and 16 shown are made of colored material. This further reducesthe intensity of the light transmitted to the clear central portion 20.Alternatively, the loops can be made of clear material similar to thatused in the central portion 20. The same discussion applies tointracorneal lens and the edge effect of course. The diameter of theclear and colored portions are predetermined based on the specificdesign of the lens. Positioning holes or locating holes 18a-18n areprovided in the colored area, as are radial loop holes 15 and 17 forsecuring loops to the lens optic 12.

FIG. 2 shows a sectional view of the lens of FIG. 1 along the line 2--2.The colored portion 12 extends annularly from the rear surface 24 to thefront surface 26.

FIG. 3 shows as cross section of a rod. The lens and loops can be lathedfrom a single rod of material as illustrated FIG. 3 where the darkerouter ring is blue and the center portion clear. The lens loops as suchcould be lathe cut as illustrated in dashed lines.

FIGS. 4a, 4b, and 4c illustrate various stages in the fabrication of therod from which lenses are cut by conventional means. The initial rod orboule 30 of clear PMMA is substantially larger in diameter than thefinished lens, and can be as long as is convenient to handle. The boule30 is then coated with a uniform layer 32 of colored PMMA as shown inFIG. 4b.

The colored layer 32 can be applied to the boule 30 by passing the boule30 through an extrusion dye having a diameter selected to apply thecolored layer 32 over the desired thickness of layer 30. Alternatively,the colored layer 32 could be fabricated as a tube and the clear innerportion 30 applied by extruding it into the central portion of the tubeor by other known processes. The resulting article is then heated anddrawn to the desired diameter in the range of 6 mm to 9 mm as shown inFIG. 4c. The drawn rod 36 provides the raw stock from which the lensescan be lathe cut by conventional processes.

FIGS. 5a, 5b, and 5c illustrate an alternative method of manufacture.The clear PMMA rod or boule 40 has a diameter substantially greater thanthe diameter of the finished lens. The boule 40 is then treated with asuitable dye, preferably blue in color, to create a colored outer layer42, as shown in FIG. 5b, which is effective to reduce the transmissionof light from the periphery of the finished lens to the central portion.The resulting article 46 is then heated and drawn to the desiredfinished diameter as illustrated in FIG. 5c.

FIG. 6 is an enlarged view of the portion of FIG. 5c enclosed with thedotted line. It can be observed that the colored portion 42 is actuallya graded region, being darker at the periphery and lighter toward thecenter of the boule. The range of the gradation can be controlled by thedegree of reduction in diameter as the boule is drawn. The greater thedegree of reduction in diameter, the sharper the optical gradient as afunction of I/R². This technique can be used to provide the mostsuitable gradient.

While it is contemplated that the intermediate product of FIGS. 4b and5b will be the preferred technique for fabrication of the lenses, it isalso possible to draw a clear boule to the desired finished diameter andthen introduce the dye to form the layer 42.

The preferred embodiments are shown with discrete positioning loopswhich are attached to the lens. Alternatively, and most preferably, thelens and loops can be fabricated such as by lathe cutting from a singlepiece of PMMA or polysulfone having a clear central portion and acolored peripheral portion. Likewise, an intracorneal lens is by lathecutting.

Full advantages of the invention is obtained when the lens has a clearcentral portion, and a colored ring or rimmed peripheral portion andcolored loops. In some situations it can be desirable to color only theloops or only the edge of the lens. By lathing loops from the coloredportion of the rod and lathing the optic from the clear portion of therod, there is manufactured a single piece lens with colored loops andpartially colored optic.

It is claimed:
 1. An intraocular lens having a clear central lensportion and a peripheral lens portion, said peripheral lens portionhaving a reduced, graded transmissivity ranging from lowest at the outerextremity thereof to highest at the junction with said clear centrallens portion, said peripheral lens portion extending completely aboutthe periphery of said clear central lens portion.
 2. An intraocular lensaccording to claim 1 including positioning loops attached to theperipheral lens portion.
 3. An intraocular lens according to claim 1including positioning holes in said peripheral portion.
 4. Anintraocular lens according to claim 1 including radial loop holes insaid peripheral portion.
 5. An intraocular lens according to claim 2wherein said reduced transmissivity peripheral portion is colored tosubstantially reduce edge effect glare.
 6. An intraocular lens accordingto claim 5 wherein said loops are of colored material.
 7. An intraocularlens according to claim 5 wherein the colored portion is blue or green.8. An intraocular lens according to claim 6 wherein the colored materialis blue.